era or epoch
Creatures
Time
Land
Trouble
100

the oldest era of the phanerozoic eon

Paleozoic Era

100

Dominant Mesozoic land vertebrates

Dinosaur

100

A large division of geologic time, but smaller than an eon

Era

100

grooves in solid rock formations made by rocks that are carried by glaciers

Glacial groove

100

an oxygen-poor environment where, over a period of time, decaying plant material changes into coal

Coal Swamp

200

The current epoch of geologic time that began 10,000 years ago

Holocene epoch

200

Mesozoic flying reptile with large, batlike wings

Pterosaur

200

The longest unit of geologic time

Eon

200

a body of water formed when ocean water floods continents

Inland Sea

200

the extinction of many species on Earth within a short period of time

Mass Extinction

300

The middle era of the Phanerozoic eon

Mesozoic Era

300

Mesozoic marine reptile with a small head, long neck, and flippers

Plesiosaur

300

A division of geologic time smaller than a period

Epoch

300

a landform that connects two continents that were previously separated

Land Bridge

300

the separation of a population of organisms from the rest of its species 

geographic isolation

400

The first epoch of the Quarternary period

Pleistocene epoch

400

Large mammal of the Cenozoic Era

Mega-Mammal

400

A unit of geologic time smaller than an era

Period

400

an ancient landmass that separated into present-day continents

Supercontinent

400

Scientist hypothesize that volcanism and _____ caused mass extinction of dinosaurs

meteorite impact

500

The youngest era of the Phanerozoic Eon

Cenosoic Era

500

Walked with their legs positioned directly below their hips

Dinosaur

500

a period of time when a large portion of Earth's surface is covered by glaciers

Ice Age

500

Separated populations of species involve in different ways as they adapt to

different environment

500

volcanic eruptions led to dust in atmosphere, plants died, animals died - this species could not adapt to the changes

Mesozoic vertebrate species

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